The microstructure of a small-particle plasma spray
(SPPS) aluminum oxide coating sprayed onto a prepared
mild steel substrate has been characterized using a variety
of microscopic techniques as part of a process optimization
study. The coating was highly conforming to the substrate
as evidenced in high-resolution transmission electron microscopy,
although some voids were present at the interface.
The layered splat microstructure, characteristic of
conventional plasma-sprayed coatings but smaller in size,
was discerned in partially thinned samples in a focused-ion-
beam scanning electron microscope (FIB-SEM). Microcracks
and microporosity, generally less than 0.5 μm in
size, was also seen between splats using transmission electron
microscopy. Cubic alumina of the crystallographic
form γ-Al_2O_3 was identified by electron diffraction.

Microstructural Characterization of Small-Particle Plasma Spray Coatings

Message from the President and lists of MSA council members, MSA appointed officers, MSA sustaining members, and MSA awards and award winners.

/pdf/microscopy-society-of-america-3fhdw9772r.pdf

Microscopy society of america

Advanced Techniques in TEM Specimen Preparation

Nanowire Alignment: Techniques, Quantification, and Applications in Large-Area Devices

The recent development of Dual-BeamTM or Cross-BeamTM FIB systems has gradually taken over the traditional single beam FIB systems. A typical FIB column contains a liquid metal ion source that produces a finely focused Ga ion beam. The primary Ga ion beam is accelerated by 30-50 kV, and directed towards the features of interest on the specimen. The incident ion beam will sputter atoms from the specimen surface, producing both secondary ions and secondary electrons. Depending on the application, the beam current can be set to high (e.g. over 60 nA) for rapid ion beam milling. Aside from electron beam imaging, operator can perform high-resolution ion beam imaging (up to 2.5 nm imaging resolution in some FIB systems). Site-specific micro-depositions (e.g., Pt, W, C, and SiO2) and microetching can also be achieved by the interaction of the primary ion beam (or electron beam) with the deposition (or etching) gas introduced into the system. Figure 1 shows a schematic diagram of ion-specimen interaction in FIB microscopes.

/pdf/advanced-techniques-in-tem-specimen-preparation-2yvclko54x.pdf

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

Characterization ZnO Nanowires Synthesized by Vapor Trapping CVD Method

The results of TEM analyses of materials are critically dependent on the quality of the sample
prepared. Although numerous techniques have been developed in the last two decades, differential
thinning of inhomogeneous materials remains a serious problem. Recently, focused ion beam (FIB)
technique has been introduced for cross-sectional sample preparation for TEM and SEM. 
A novel system for depositing a fine-grain (~200 nm) ceramic coating on a metal surface via
a patent pending Small-Particle Plasma Spray (SPPS) technique has been developed at the Basic
Industry Research Laboratory of Northwestern University. To understand the properties of the
coated surface, the ceramic/metal interface and the microstructure of the ceramic coating must be
investigated. This paper presents a comparison of the microstructure of an Al_2O_3 coating on a mild
steel substrate prepared using conventional and FIB techniques.

Comparison of Focused Ion Beam and Conventional Techniques on TEM Specimen Preparation of Metal-Ceramic Interfaces

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1431927604886288

Microstructure of Ultra Fine Grain Al 5083 After High Temperature Deformation

The development of advanced materials, with complex microstructures, is a permanent challenge to the development and application of new efficient techniques for microstructural characterization. In ceramic coatings on metals, there exist a differential ion-milling ratio between both components, limiting in principle the use of conventional techniques. In this work, we report on a comparative study of TEM sample preparation techniques for plasma-sprayed ceramic coatings. Firstly, we have used a procedure derived from the conventional one (polishing, dimpling, ion milling), and alternatively a new technique using focused ion-beam milling. The material selected for this study is fine-grained alumina that was plasma-sprayed on a steel substrate. The efficiency of both techniques is discussed along with the most significant microstructural features of the material subject of study.

/pdf/estudio-comparativo-de-tecnicas-de-preparacion-de-muestras-1wq2yvly4r.pdf

Estudio comparativo de técnicas de preparación de muestras para microscopía electrónica de transmisión de recubrimientos cerámicos proyectados por plasma

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1431927604886306

Wen-An Chiou

Papers

Characterization ZnO Nanowires Synthesized by Vapor Trapping CVD Method

Comparison of Focused Ion Beam and Conventional Techniques on TEM Specimen Preparation of Metal-Ceramic Interfaces

Microstructure of Ultra Fine Grain Al 5083 After High Temperature Deformation

Estudio comparativo de técnicas de preparación de muestras para microscopía electrónica de transmisión de recubrimientos cerámicos proyectados por plasma

Low Temperature Grain Growth Behavior in Nanocrystalline Ni